Patent Grant
9043517
The disclosed embodiments relate generally to memory systems, and in particular, to using non-volatile data storage systems to implement Bloom filters.
Semiconductor memory devices, including flash memory, typically utilize memory cells to store data as an electrical value, such as an electrical charge or voltage. A flash memory cell, for example, includes a single transistor with a floating gate that is used to store a charge representative of a data value. Flash memory is a non-volatile data storage device that can be electrically erased and reprogrammed. Non-volatile memory retains stored information even when not powered, as opposed to volatile memory, which requires power to maintain the stored information. In an address-targeted write to memory, a host supplies an address and the data to be written. In an address-targeted read from memory, a host supplies an address from which to read. However, when memory is used to implement data structures such as Bloom filters, using address-targeted read and write methods to access memory is not ideal.
Various implementations of systems, methods and devices within the scope of the appended claims each have several aspects, no single one of which is solely responsible for the attributes described herein. Without limiting the scope of the appended claims, after considering this disclosure, and particularly after considering the section entitled “Detailed Description” one will understand how the aspects of various implementations are used to enable multipass programming in buffers implemented in non-volatile data storage systems (e.g., using one or more flash memory devices). In one aspect, a portion of memory (e.g., a page in a block of a flash memory device) may be programmed many (e.g., 1000) times before the contents of the portion of memory need to be moved to a new (e.g., unused) location in the memory.
So that the present disclosure can be understood in greater detail, a more particular description may be had by reference to the features of various implementations, some of which are illustrated in the appended drawings. The appended drawings, however, merely illustrate the more pertinent features of the present disclosure and are therefore not to be considered limiting, for the description may admit to other effective features.
In accordance with common practice the various features illustrated in the drawings may not be drawn to scale. Accordingly, the dimensions of the various features may be arbitrarily expanded or reduced for clarity. In addition, some of the drawings may not depict all of the components of a given system, method or device. Finally, like reference numerals may be used to denote like features throughout the specification and figures.
Many applications use a data structure called a Bloom filter to determine whether an element is a member of a set (e.g., whether an object is already physically present in a storage media). Bloom filter arrays (the storage aspect of a Bloom filter) can be implemented with dynamic random-access memory (DRAM), but this can become prohibitively expensive as the size of the set grows. In embodiments disclosed below, for applications where large Bloom filters are needed, NAND flash storage devices are used.
The various implementations described herein include systems, methods and/or devices used to enable multipass programming in buffers implemented in non-volatile data storage systems (e.g., using one or more flash memory devices). Some implementations include systems, methods and/or devices to integrate Bloom filter functionality in the non-volatile data storage system, where a portion of memory storing one or more bits of a Bloom filter array may be programmed many (e.g., 1000) times before the contents of the portion of memory need to be moved to a new (e.g., unused) location in the memory.
More specifically, some implementations include a method for data processing. In some implementations, at a non-volatile data storage system, the method includes receiving from a host a plurality of requests that specify respective elements. The method further includes, for each respective element specified by the received requests, (1) generating a respective set of k bit positions in a Bloom filter, using k distinct hash functions, where k is an integer greater than 2, and (2) setting the respective set of k bit positions in the Bloom filter, wherein the Bloom filter is stored in a non-volatile storage medium of the non-volatile data storage system. Further, in some embodiments, setting a respective bit position of the k bit positions in the Bloom filter includes (1) accessing usage information for a storage medium portion of the non-volatile storage medium that includes the respective bit position in the Bloom filter, (2) determining whether the usage information for the storage medium portion meets predefined multipass programming criteria, (3) if the usage information for the storage medium portion meets the predefined multipass programming criteria, setting the respective bit position in the Bloom filter in the storage medium portion, and (4) if the usage information for the storage medium portion does not meet the predefined multipass programming criteria, identifying a respective unused portion of the non-volatile storage medium, copying Bloom filter information in the storage medium portion to the identified portion of the non-volatile storage medium, and setting the respective bit position in the Bloom filter.
In some embodiments, the method includes generating the respective set of k bit positions in the Bloom filter using one or more processors of the non-volatile data storage system.
In some embodiments, the method includes generating the respective set of k bit positions in the Bloom filter using k parallel processors of the non-volatile data storage system.
In some embodiments, if the usage information for the storage medium portion does not meet the predefined multipass programming criteria, the method further includes scheduling erasure of the storage medium portion of the non-volatile storage medium.
In some embodiments, scheduling erasure of the storage medium portion is performed after setting the respective bit position in the Bloom filter.
In some embodiments, determining whether the usage information for the storage medium portion meets predefined multipass programming criteria includes (1) determining whether the usage information indicates the storage medium portion of the non-volatile data storage system has been programmed no more than m times, where m is an integer of at least 1000, (2) if the storage medium portion of the non-volatile data storage system has been programmed no more than m times, the usage information for the storage medium portion meets the predefined multipass programming criteria, and (3) if the storage medium portion of the non-volatile data storage system has been programmed more than m times, the usage information for the storage medium portion does not meet the predefined multipass programming criteria.
In some embodiments, setting the respective set of k bit positions in the storage medium includes out of order word line programming.
In some embodiments, the method further includes receiving an element for testing with respect to the Bloom filter. The method further includes testing whether the element is present in the Bloom filter, by (1) processing the element with the k distinct hash functions to generate a set of k bit positions, (2) reading the set of k bit positions from the Bloom filter, (3) returning a first result if all the k bit positions in the Bloom filter from the set are set, and (4) returning a second result if one or more of the k bit positions in the Bloom filter from the set are not set.
In some embodiments, the non-volatile storage medium includes one or more flash memory devices.
In some embodiments, the non-volatile data storage system is distinct from the host.
In some embodiments, the non-volatile data storage system is embedded in the host.
In some embodiments, the respective elements specified by the plurality of requests comprise a plurality of objects.
In some embodiments, the respective elements specified by the plurality of requests comprise n-bit fingerprints of a plurality of objects, where n is at least 64.
In another aspect, any of the methods described above are performed by a non-volatile data storage system comprising (1) a non-volatile storage medium storing a Bloom filter, (2) one or more processors, and (3) memory storing one or more programs, which when executed by the one or more processors cause the non-volatile data storage system to perform any of the methods described above.
In yet another aspect, a non-transitory computer readable storage medium stores one or more programs configured for execution by one or more processors of a non-volatile data storage system, the one or more programs comprising instructions for causing the non-volatile data storage system to perform any of the methods described above.
In yet another aspect, a non-volatile data storage system is configured to process data in accordance with any of the methods described above. In some embodiments, the non-volatile data storage system includes means for receiving from a host a plurality of requests that specify respective elements, and means for processing each respective element specified by the received requests, including (1) means for generating a respective set of k bit positions in a Bloom filter, using k distinct hash functions, where k is an integer greater than 2, and (2) means for setting the respective set of k bit positions in the Bloom filter, wherein the Bloom filter is stored in a non-volatile storage medium of the non-volatile data storage system. Further, in some embodiments, the means for setting includes means for setting a respective bit position of the k bit positions in the Bloom filter, which includes (1) means for accessing usage information for a storage medium portion of the non-volatile storage medium that includes the respective bit position in the Bloom filter, (2) means for determining whether the usage information for the storage medium portion meets predefined multipass programming criteria, (3) means for setting the respective bit position in the Bloom filter in the storage medium portion if the usage information for the storage medium portion meets the predefined multipass programming criteria, and (4) means for identifying a respective unused portion of the non-volatile storage medium, copying Bloom filter information in the storage medium portion to the identified portion of the non-volatile storage medium, and setting the respective bit position in the Bloom filter, if the usage information for the storage medium portion does not meet the predefined multipass programming criteria.
Numerous details are described herein in order to provide a thorough understanding of the example implementations illustrated in the accompanying drawings. However, some embodiments may be practiced without many of the specific details, and the scope of the claims is only limited by those features and aspects specifically recited in the claims. Furthermore, well-known methods, components, and circuits have not been described in exhaustive detail so as not to unnecessarily obscure more pertinent aspects of the implementations described herein.
Computer system 110 is coupled to memory controller 120 through data connections 101. However, in some implementations computer system 110 includes memory controller 120 as a component and/or a sub-system. Computer system 110 may be any suitable computer device, such as a computer, a laptop computer, a tablet device, a netbook, an internet kiosk, a personal digital assistant, a mobile phone, a smart phone, a gaming device, a computer server, or any other computing device. Computer system 110 is sometimes called a host or host system. In some implementations, computer system 110 includes one or more processors, one or more types of memory, a display and/or other user interface components such as a keyboard, a touch screen display, a mouse, a track-pad, a digital camera and/or any number of supplemental devices to add functionality.
Storage medium 130 is coupled to memory controller 120 through connections 103. Connections 103 are sometimes called data connections, but typically convey commands in addition to data, and optionally convey metadata, error correction information and/or other information in addition to data values to be stored in storage medium 130 and data values read from storage medium 130. In some implementations, however, memory controller 120 and storage medium 130 are included in the same device as components thereof. Furthermore, in some implementations memory controller 120 and storage medium 130 are embedded in a host device, such as a mobile device, tablet, other computer or computer controlled device, and the methods described herein are performed by the embedded memory controller. Storage medium 130 may include any number (i.e., one or more) of memory devices including, without limitation, non-volatile semiconductor memory devices, such as flash memory. For example, flash memory devices can be configured for enterprise storage suitable for applications such as cloud computing, or for caching data stored (or to be stored) in secondary storage, such as hard disk drives. Additionally and/or alternatively, flash memory can also be configured for relatively smaller-scale applications such as personal flash drives or hard-disk replacements for personal, laptop and tablet computers. Furthermore, as discussed in more detail below, flash memory devices can be configured to implement data structures such as Bloom filter array(s) 131.
A Bloom filter (e.g., Bloom filter array(s) 131) is a probabilistic data structure used to determine if an element “x” is a member of a set “S” with high probability. A Bloom filter is constructed using an N-bit array that is initially cleared, and has hash functions where 0≦Hash (x,k)≦N−1. For each element “x” in set “S,” k hash functions are computed, and the k corresponding bits in the N-bit array are set. In some embodiments, a Bloom filter is initially cleared by resetting the N-bit array to all zeros, and the k corresponding bits in the N-bit array are set to ones. In some embodiments, a Bloom filter is initially cleared by resetting the N-bit array to all ones, and the k corresponding bits in the N-bit array are set to zeros. While the labeling of memory cell states as having specific data values is somewhat arbitrary, with respect to flash memory devices, memory cells that have been reset are typically said to represent ones, and memory cells that have been set are typically said to represent zeros. However, any labeling or mapping of memory cell states to data values can be used, as long as it is used consistently.
As an example, to test an element “w” for membership in the set “S,” the k hash functions are generated for element “w” and the k bit positions are tested. If the k bit positions are set, then the element “w” is most likely a member of set “S,” with a possibility of this membership being a “false positive.” A false positive is when the Bloom filter returns a result that an element is a member of the set “S,” when in actuality it is not. Bloom filters return fewer false positives when the number of elements in the set “S” is an order of magnitude smaller than the number of bits in the bit array. The probability of a false positive is given by equation (1):
(1−e−k(n+0.5)/(m−1))k (1)
In equation (1), k represents the number of hash functions per element, m represents the number of bits in the Bloom filter, and n is the number of elements stored in the Bloom filter.
Storage medium 130 is divided into a number of addressable and individually selectable blocks. In some implementations, the individually selectable blocks are the minimum size erasable units in a flash memory device. In other words, each block contains the minimum number of memory cells that can be erased simultaneously. Each block is usually further divided into a plurality of pages and/or word lines, where each page or word line is typically an instance of the smallest individually accessible (readable) portion in a block. In some implementations (e.g., using some types of flash memory), the smallest individually accessible unit of a data set, however, is a sector, which is a subunit of a page. That is, a block includes a plurality of pages, each page contains a plurality of sectors, and each sector is the minimum unit of data for reading data from the flash memory device.
For example, one block comprises any number of pages, for example, 64 pages, 128 pages, 256 pages or another suitable number of pages. Blocks are typically grouped into a plurality of zones. Each block zone can be independently managed to some extent, which increases the degree of parallelism for parallel operations and simplifies management of storage medium 130.
In some implementations, memory controller 120 includes a management module 121, a host interface 129, a storage medium interface (I/O) 128, and additional module(s) 125. Memory controller 120 may include various additional features that have not been illustrated for the sake of brevity and so as not to obscure more pertinent features of the example implementations disclosed herein, and a different arrangement of features may be possible. Host interface 129 provides an interface to computer system 110 through data connections 101. Similarly, storage medium I/O 128 provides an interface to storage medium 130 though connections 103. In some implementations, storage medium I/O 128 includes read and write circuitry, including circuitry capable of providing reading signals to storage medium 130 (e.g., reading threshold voltages for NAND-type flash memory).
In some implementations, management module 121 includes one or more processing units (CPUs, also sometimes called processors) 122 configured to execute instructions in one or more programs (e.g., in management module 121). In some implementations, the one or more CPUs 122 are shared by one or more components within, and in some cases, beyond the function of memory controller 120. Management module 121 is coupled to host interface 129, additional module(s) 125 and storage medium I/O 128 in order to coordinate the operation of these components.
Additional module(s) 125 are coupled to storage medium I/O 128, host interface 129, and management module 121. As an example, additional module(s) 125 may include an error control module to limit the number of uncorrectable errors inadvertently introduced into data during writes to memory or reads from memory. In some embodiments, additional module(s) 125 are executed in software by the one or more CPUs 122 of management module 121, and, in other embodiments, additional module(s) 125 are implemented in whole or in part using special purpose circuitry (e.g., to perform encoding and decoding functions).
During an address-targeted write operation, host interface 129 receives data to be stored in storage medium 130 from computer system 110. The data held in host interface 129 is made available to an encoder (e.g., in additional module(s) 125), which encodes the data to produce one or more codewords. The one or more codewords are made available to storage medium I/O 128, which transfers the one or more codewords to storage medium 130 in a manner dependent on the type of storage medium being utilized.
An address-targeted read operation is initiated when computer system (host) 110 sends one or more host read commands on control line 111 to memory controller 120 requesting data from storage medium 130. Memory controller 120 sends one or more read access commands to storage medium 130, via storage medium I/O 128, to obtain raw read data in accordance with memory locations (addresses) specified by the one or more host read commands. Storage medium I/O 128 provides the raw read data (e.g., comprising one or more codewords) to a decoder (e.g., in additional module(s) 125). If the decoding is successful, the decoded data is provided to host interface 129, where the decoded data is made available to computer system 110. In some implementations, if the decoding is not successful, memory controller 120 may resort to a number of remedial actions or provide an indication of an irresolvable error condition.
Bloom filter implementations using address-targeted write and read operations would require transferring large amounts of data between computer system (host) 110 and data storage system 100. For example, to add an object “X” to Bloom filter array(s) 131, computer system 110 would generate k hashes and then initiate k read-modify-write commands to data storage system 100. In some examples, this would require the sensing, transfer, modification, and write back of k×4 KB pages. As another example, to test an element for presence in Bloom filter array(s) 131, computer system 110 would initiate k read commands. Instead of using address-targeted write and read operations, which require computer system 110 to generate k hashes and/or initiate k commands to data storage system 100, Bloom filter functionality is integrated in data storage system 100, as described below and with reference to
When Bloom filter functionality is integrated in data storage system 100, computer system 110 is not required to generate k hashes and initiate k commands in order to add an object “X” to Bloom filter array(s) 131. Instead, in some implementations, computer system 110 transfers object “X” directly to data storage system 100 as an element to add to Bloom filter array(s) 131. In some implementations, computer system 110 generates a fingerprint of object “X” (e.g., an n-bit fingerprint of object “X,” where n is at least 64) and transfers the fingerprint of object “X” directly to data storage system 100 as an element to add to Bloom filter array(s) 131. For each element received from computer system 110 to add to Bloom filter array(s) 131, data storage system 100 generates k bit positions in Bloom filter array(s) 131, using k distinct hash functions, where k is an integer greater than 2. Further, data storage system 100 sets the k bit positions in Bloom filter array(s) 131 (e.g., using write circuitry in storage medium I/O 128). Thus, only a single host command (e.g., “Add Element”) is needed to add an element to Bloom filter array(s) 131, reducing data transfers between computer system 110 and memory controller 120.
Further, when Bloom filter functionality is integrated in data storage system 100, computer system 110 is not required to initiate k read commands in order to test whether an element is present in Bloom filter array(s) 131. Instead, similar to the process described above for adding an element to Bloom filter array(s) 131, in some implementations, computer system 110 transfers an element (e.g., object “X” or a fingerprint of object “X”) directly to data storage system 100 in order to test whether the element is present in Bloom filter array(s) 131. For each element received from computer system 110 for testing, data storage system 100 processes the element with k distinct hash functions to generate k bit positions in Bloom filter array(s) 131 and reads the k bit positions from Bloom filter array(s) 131 (e.g., using read circuitry in storage medium I/O 128). In some embodiments, data storage system 100 returns a first result in accordance with a determination that all the k bit positions are set (e.g., indicating that the element is present in Bloom filter array(s) 131 with high probability) or returns a second result in accordance with a determination that at least a predetermined number (e.g., one or more) of the k bit positions in the Bloom filter are not set (e.g., indicating that the element is not present in Bloom filter array(s) 131). Thus, only a single host command (e.g., “Test Element”) is needed to test for an element's presence in Bloom filter array(s) 131, reducing data transfers between computer system 110 and memory controller 120.
In some implementations, computer system 110 resets Bloom filter array(s) 131 with a single host command (e.g., “Reset Filter”). Data storage system 100 responds to a reset command by resetting Bloom filter array(s) 131 to an empty state. In some embodiments, Bloom filter array(s) 131 is cleared by resetting the array to all zeros. In some embodiments, Bloom filter array(s) 131 is cleared by resetting the array to all ones. As explained above, with respect to flash memory devices, memory cells that have been reset are typically said to represent ones.
When Bloom filter functionality is integrated in data storage system 100, data transfers between storage medium I/O 128 and storage medium 130 can also be reduced. In some embodiments, storage medium 130 is implemented using NAND flash memory. NAND flash memory devices have on-chip logical function capabilities with the ability to do simple bit-wise operations (e.g., AND, OR, INVERT, and XOR). Bloom filters require the ability to test and set single bits at a time. By using the NAND flash memory device's integrated logical function registers, these calculations are offloaded from the drive's processor(s) (e.g., CPUs 122), allowing for higher performance.
Flash memory devices utilize memory cells to store data as electrical values, such as electrical charges or voltages. Each flash memory cell typically includes a single transistor with a floating gate that is used to store a charge, which modifies the threshold voltage of the transistor (i.e., the voltage needed to turn the transistor on). The magnitude of the charge, and the corresponding threshold voltage the charge creates, is used to represent one or more data values. In some implementations, during a read operation, a reading threshold voltage is applied to the control gate of the transistor and the resulting sensed current or voltage is mapped to a data value.
The terms “cell voltage” and “memory cell voltage,” in the context of flash memory cells, means the threshold voltage of the memory cell, which is the minimum voltage that needs to be applied to the gate of the memory cell's transistor in order for the transistor to conduct current. Similarly, reading threshold voltages (sometimes also called reading signals and reading voltages) applied to a flash memory cells are gate voltages applied to the gates of the flash memory cells to determine whether the memory cells conduct current at that gate voltage. In some implementations, when a flash memory cell's transistor conducts current at a given reading threshold voltage, indicating that the cell voltage is less than the reading threshold voltage, the raw data value for that read operation is a “1,” and otherwise the raw data value is a “0.”
In some embodiments, the add element module 218 optionally includes the following modules or sub-modules, or a subset thereof:
In some embodiments, the test element module 224 optionally includes the following modules or sub-modules, or a subset thereof:
In some embodiments, the delete element module 232 optionally includes the following modules or sub-modules, or a subset thereof:
Each of the above identified elements may be stored in one or more of the previously mentioned memory devices, and corresponds to a set of instructions for performing a function described above. The above identified modules or programs (i.e., sets of instructions) need not be implemented as separate software programs, procedures or modules, and thus various subsets of these modules may be combined or otherwise re-arranged in various embodiments. In some embodiments, memory 206 may store a subset of the modules and data structures identified above. Furthermore, memory 206 may store additional modules and data structures not described above. In some embodiments, the programs, modules, and data structures stored in memory 206, or the computer readable storage medium of memory 206, provide instructions for implementing any of the methods described below with reference to
Although
As discussed below with reference to
Sequential voltage ranges 301 and 302 between source voltage VSS and drain voltage VDD are used to represent corresponding bit values “1” and “0,” respectively. Each voltage range 301, 302 has a respective center voltage V1 301b, V0 302b. As described below, in many circumstances the memory cell current sensed in response to an applied reading threshold voltages is indicative of a memory cell voltage different from the respective center voltage V1 301b or V0 302b corresponding to the respective bit value written into the memory cell. Errors in cell voltage, and/or the cell voltage sensed when reading the memory cell, can occur during write operations, read operations, or due to “drift” of the cell voltage between the time data is written to the memory cell and the time a read operation is performed to read the data stored in the memory cell. For ease of discussion, these effects are collectively described as “cell voltage drift.” Each voltage range 301, 302 also has a respective voltage distribution 301a, 302a that may occur as a result of any number of a combination of error-inducing factors, examples of which are identified above.
In some implementations, a reading threshold voltage VR is applied between adjacent center voltages (e.g., applied proximate to the halfway region between adjacent center voltages V1 301b and V0 302b). Optionally, in some implementations, the reading threshold voltage is located between voltage ranges 301 and 302. In some implementations, reading threshold voltage VR is applied in the region proximate to where the voltage distributions 301a and 302a overlap, which is not necessarily proximate to the halfway region between adjacent center voltages V1 301b and V0 302b.
As explained above, a SLC memory device stores one bit of information (“0” or “1”) per memory cell. In some embodiments, a Bloom filter is implemented in a SLC memory device, and uses a single-level flash memory cell for each bit of the N-bit array of the Bloom filter. In some embodiments (e.g., using some types of flash memory), the Bloom filter is initially cleared by resetting each bit of the N-bit array to “1” and elements are added to the Bloom filter by setting the corresponding k bits generated from the k hash functions to “0.” In some embodiments, the Bloom filter is initially cleared by resetting each bit of the N-bit array to “0” and elements are added to the Bloom filter by setting the corresponding k bits generated from the k hash functions to “1.”
In order to increase storage density in flash memory, flash memory has developed from single-level (SLC) cell flash memory to multi-level cell (MLC) flash memory so that two or more bits can be stored by each memory cell. A MLC flash memory device is used to store multiple bits by using voltage ranges within the total voltage range of the memory cell to represent different bit-tuples. A MLC flash memory device is typically more error-prone than a SLC flash memory device created using the same manufacturing process because the effective voltage difference between the voltages used to store different data values is smaller for a MLC flash memory device. Moreover, due to any number of a combination of factors, such as electrical fluctuations, defects in the storage medium, operating conditions, device history, and/or write-read circuitry, a typical error includes a stored voltage level in a particular MLC being in a voltage range that is adjacent to the voltage range that would otherwise be representative of the correct storage of a particular bit-tuple. The impact of such errors can be reduced by gray-coding the data, such that adjacent voltage ranges represent single-bit changes between bit-tuples.
As explained above, a storage medium (e.g., storage medium 130,
At least in some implementations, method 400 is performed by a non-volatile data storage system (e.g., data storage system 100,
A non-volatile data storage system (e.g., data storage system 100,
In some embodiments, the non-volatile data storage system is (404) distinct from the host. For example, in some implementations, one or more components of the non-volatile data storage system (e.g., memory controller 120 and storage medium 130 of data storage system 100,
In some embodiments, the non-volatile data storage system is (406) embedded in the host. In some implementations, one or more components of the non-volatile data storage system (e.g., memory controller 120 and storage medium 130 of data storage system 100,
In some embodiments, the respective elements specified (408) by the plurality of requests comprise a plurality of objects. In some implementations, for example, an object is a file (e.g., a 1 MB file). In some implementations, for example in data deduplication applications, an object is an email attachment in a forwarded email message. In some implementations, an object is mapped into an n-bit fingerprint by the non-volatile data storage system (e.g., data storage system 100,
In some embodiments, the respective elements specified (410) by the plurality of requests comprise n-bit fingerprints of a plurality of objects, where n is at least 64. In some implementations, an object is mapped into an n-bit number by a host (e.g., computer system 110,
Next, for each respective element specified (412) by the received request, the non-volatile data storage system generates (414) a respective set of k bit positions (sometimes called a respective group of k bit positions) in a Bloom filter, using k distinct hash functions, where k is an integer greater than 2. As an example, if k is equal to 16, for a respective element specified in the received request, the non-volatile data storage system uses 16 distinct hash functions to generate a respective set of 16 bit positions in the Bloom filter. In some implementations, the respective set of k bit positions in the Bloom filter is generated in firmware (e.g., in management module 121,
In some embodiments, the non-volatile data storage system generates (416) the respective set of k bit positions in the Bloom filter using one or more processors of the non-volatile data storage system (e.g., CPUs 122,
In some embodiments, the non-volatile data storage system generates (418) the respective set of k bit positions in the Bloom filter using k parallel processors of the non-volatile data storage system. In some other embodiments, the non-volatile data storage system generates the respective set of k bit positions in the Bloom filter using at least k/2 parallel processors of the non-volatile data storage system, while in yet other embodiments, the non-volatile data storage system generates the respective set of k bit positions in the Bloom filter using at least k/4 parallel processors of the non-volatile data storage system. In some implementations, the aforementioned one or more processors of the non-volatile data storage system (e.g., CPUs 122,
Furthermore, for each respective element specified (412) by the received request, the non-volatile data storage system sets (420) the respective set of k bit positions in the Bloom filter (e.g., Bloom filter array(s) 131,
In some embodiments, the non-volatile storage medium comprises (422) one or more flash memory devices. In some implementations, the non-volatile storage medium (e.g., storage medium 130,
In some embodiments, setting (424) the respective set of k bit positions in the storage medium includes out of order word line programming. In some embodiments, out of order word line programming includes setting one or more bits on a first word line, the first word line positioned earlier in a block, subsequent to setting one or more bits on a second word line, the second word line positioned later in the block. For example, if a block has 128 word lines (e.g., word line 0 through word line 127), in order word line programming usually involves writing word line 0, word line 1, word line 2, . . . , word line 126, and word line 127, in ascending order. An example of out of order word line programming includes writing word line 17 (e.g., setting one or more bits on word line 17) after writing word line 25 (e.g., setting one or more bits on word line 25).
In some embodiments, setting (426) a respective bit position of the k bit positions in the Bloom filter comprises accessing (428) usage information for a storage medium portion (e.g., a page, a word line, or a sector) of the non-volatile storage medium (e.g., storage medium 130,
Next, setting (426) a respective bit position of the k bit positions in the Bloom filter further comprises determining (430) whether the usage information for the storage medium portion (e.g., a page, a word line, or a sector) meets predefined multipass programming criteria. For example, in some embodiments, if the respective bit position to be set in the Bloom filter is stored on word line 15, the non-volatile data storage system determines whether the usage information for word line 15 meets predefined multipass programming criteria.
In some embodiments, determining (430) whether the usage information for the storage medium portion meets predefined multipass programming criteria comprises determining (432) whether the usage information indicates the storage medium portion (e.g., a page, a word line, or a sector) of the non-volatile data storage system has been programmed no more than m times, where m is an integer of at least 1000. As used herein, the term “no more than m” may be construed to mean “less than or equal to m.” For example, if m is equal to 1000, determining whether the usage information indicates the storage medium portion has been programmed no more than 1000 times is the same as determining whether the usage information indicates the storage medium portion has been programmed less than or equal to 1000 times.
Further, in some embodiments, in accordance with a determination that the storage medium portion of the non-volatile data storage system has been programmed no more than m times, the usage information for the storage medium portion meets (434) the predefined multipass programming criteria. As an example, if m is equal to 1000 and the respective bit position is on word line 15, if the usage information for word line 15 indicates that word line 15 has been programmed 1000 times or less, then the usage information for word line 15 meets the predefined multipass programming criteria.
Further, in some embodiments, in accordance with a determination that the storage medium portion of the non-volatile data storage system has been programmed more than m times, the usage information for the storage medium portion does not meet (436) the predefined multipass programming criteria. As an example, if m is equal to 1000 and the respective bit position is on word line 15, if the usage information for word line 15 indicates that word line 15 has been programmed 1001 times or more, then the usage information for word line 15 does not meet the predefined multipass programming criteria.
Next, setting (426) a respective bit position of the k bit positions in the Bloom filter further comprises, in accordance with a determination that the usage information for the storage medium portion (e.g., a page, a word line, or a sector) meets the predefined multipass programming criteria, setting (440) the respective bit position in the Bloom filter in the storage medium portion. As an example, if the respective bit position to be set is on word line 15 and if it is determined that the usage information for word line 15 meets the predefined multipass programming criteria (e.g., word line 15 has been programmed no more than m times), then the non-volatile data storage system sets the respective bit position on word line 15. Further, in some implementations, setting a respective bit position of the k bit positions in the Bloom filter includes identifying the storage medium portion of the non-volatile storage medium that includes the respective bit position in the Bloom filter, and setting the respective bit position in the Bloom filter in the storage medium portion without resetting any other bit positions in the storage medium portion.
Further, setting (426) a respective bit position of the k bit positions in the Bloom filter further comprises, in accordance with a determination that the usage information for the storage medium portion (e.g., a page, a word line, or a sector) does not meet the predefined multipass programming criteria, identifying (442) a respective unused portion of the non-volatile storage medium, copying Bloom filter information in the storage medium portion to the identified portion of the non-volatile storage medium, and setting the respective bit position in the Bloom filter. As an example, if the respective bit position to be set is on word line 15 and if it is determined that the usage information for word line 15 does not meet the predefined multipass programming criteria (e.g., word line 15 has been programmed more than m times), then the non-volatile data storage system identifies an unused word line, copies Bloom filter information from word line 15 to the identified unused word line, and sets the respective bit position in the Bloom filter.
Optionally, in accordance with a determination that the usage information for the storage medium portion does not meet the predefined multipass programming criteria, the non-volatile data storage system schedules (444) erasure of the storage medium portion of the non-volatile storage medium. Using the example above where the usage information for word line 15 does not meet the predefined multipass programming criteria, the non-volatile data storage system schedules erasure of word line 15 (e.g., erasure of the block containing word line 15).
In some embodiments, scheduling (446) erasure of the storage medium portion is performed after setting the respective bit position in the Bloom filter. Using the example above where the respective bit position to be set is on word line 15 and it is determined that the usage information for word line 15 does not meet the predefined multipass programming criteria, the non-volatile data storage system identifies an unused word line, copies Bloom filter information from word line 15 to the identified unused word line, sets the respective bit position in the Bloom filter, and in some embodiments, then schedules erasure of word line 15. Alternatively, erasure of the storage medium portion is scheduled after the copying but prior to setting the respective bit position in the Bloom filter. Using the previous example, in some embodiments, the non-volatile data storage system identifies an unused word line, copies Bloom filter information from word line 15 to the identified unused word line, schedules erasure of word line 15, and then sets the respective bit position in the Bloom filter.
Optionally, the non-volatile data storage system receives (448) an element (e.g., a first element) for testing with respect to the Bloom filter. In some embodiments, a non-volatile data storage system (e.g., data storage system 100,
Next, the non-volatile data storage system tests (450) whether the element is present in the Bloom filter by processing (452) the element with the k distinct hash functions to generate a set of k bit positions (sometimes called a group of k bit positions). As an example, if k is equal to 16, the non-volatile data storage system (e.g., data storage system 100,
In some embodiments, the non-volatile data storage system generates the respective set of k bit positions in the Bloom filter using one or more processors of the non-volatile data storage system (e.g., CPUs 122,
In some embodiments, the non-volatile data storage system generates the respective set of k bit positions in the Bloom filter using k parallel processors (or, alternatively, at least k/2 parallel processors, or at least k/4 parallel processors, as discussed above) of the non-volatile data storage system. In some implementations, the aforementioned one or more processors of the non-volatile data storage system (e.g., CPUs 122,
The non-volatile data storage system further tests (450) whether the element is present in the Bloom filter by reading (454) the set of k bit positions from the Bloom filter. Using the example above where k is equal to 16, the non-volatile data storage system reads the set of 16 bit positions from the Bloom filter (e.g., Bloom filter array(s) 131,
Testing (450) whether the element is present in the Bloom filter further includes returning (456) a first result in accordance with a determination that all the k bit positions in the Bloom filter from the set are set. In some implementations, using the example above where k is equal to 16, the non-volatile data storage system (e.g., data storage system 100,
Further, testing (450) whether the element is present in the Bloom filter includes returning (458) a second result in accordance with a determination that one or more of the k bit positions in the Bloom filter from the set are not set. In some implementations, the non-volatile data storage system (e.g., data storage system 100,
In some implementations, with respect to any of the methods described above, the storage medium (e.g., storage medium 130,
In some implementations, with respect to any of the methods described above, a data storage system includes a non-volatile storage medium (e.g., storage medium 130,
It will be understood that, although the terms “first,” “second,” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first contact could be termed a second contact, and, similarly, a second contact could be termed a first contact, which changing the meaning of the description, so long as all occurrences of the “first contact” are renamed consistently and all occurrences of the second contact are renamed consistently. The first contact and the second contact are both contacts, but they are not the same contact.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the claims. As used in the description of the embodiments and the appended claims, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
As used herein, the term “if” may be construed to mean “when” or “upon” or “in response to determining” or “in accordance with a determination” or “in response to detecting,” that a stated condition precedent is true, depending on the context. Similarly, the phrase “if it is determined [that a stated condition precedent is true]” or “if [a stated condition precedent is true]” or “when [a stated condition precedent is true]” may be construed to mean “upon determining” or “in response to determining” or “in accordance with a determination” or “upon detecting” or “in response to detecting” that the stated condition precedent is true, depending on the context.
The foregoing description, for purpose of explanation, has been described with reference to specific implementations. However, the illustrative discussions above are not intended to be exhaustive or to limit the claims to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The implementations were chosen and described in order to best explain principles of operation and practical applications, to thereby enable others skilled in the art.
This application claims the benefit of U.S. Provisional Patent Application No. 61/858,528, filed on Jul. 25, 2013, which is incorporated by reference herein.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4916652 | Schwarz et al. | Apr 1990 | A |
| 5270979 | Harari et al. | Dec 1993 | A |
| 5519847 | Fandrich et al. | May 1996 | A |
| 5530705 | Malone, Sr. | Jun 1996 | A |
| 5537555 | Landry et al. | Jul 1996 | A |
| 5551003 | Mattson et al. | Aug 1996 | A |
| 5657332 | Auclair et al. | Aug 1997 | A |
| 5666114 | Brodie et al. | Sep 1997 | A |
| 5708849 | Coke et al. | Jan 1998 | A |
| 5765185 | Lambrache et al. | Jun 1998 | A |
| 5943692 | Marberg et al. | Aug 1999 | A |
| 5982664 | Watanabe | Nov 1999 | A |
| 6000006 | Bruce et al. | Dec 1999 | A |
| 6016560 | Wada et al. | Jan 2000 | A |
| 6018304 | Bessios | Jan 2000 | A |
| 6070074 | Perahia et al. | May 2000 | A |
| 6138261 | Wilcoxson et al. | Oct 2000 | A |
| 6182264 | Ott | Jan 2001 | B1 |
| 6192092 | Dizon et al. | Feb 2001 | B1 |
| 6295592 | Jeddeloh | Sep 2001 | B1 |
| 6311263 | Barlow et al. | Oct 2001 | B1 |
| 6412042 | Paterson et al. | Jun 2002 | B1 |
| 6442076 | Roohparvar | Aug 2002 | B1 |
| 6449625 | Wang | Sep 2002 | B1 |
| 6484224 | Robins et al. | Nov 2002 | B1 |
| 6516437 | Van Stralen et al. | Feb 2003 | B1 |
| 6678788 | O'Connell | Jan 2004 | B1 |
| 6757768 | Potter et al. | Jun 2004 | B1 |
| 6775792 | Ulrich et al. | Aug 2004 | B2 |
| 6810440 | Micalizzi, Jr. et al. | Oct 2004 | B2 |
| 6836808 | Bunce et al. | Dec 2004 | B2 |
| 6836815 | Purcell et al. | Dec 2004 | B1 |
| 6842436 | Moeller | Jan 2005 | B2 |
| 6871257 | Conley et al. | Mar 2005 | B2 |
| 6895464 | Chow et al. | May 2005 | B2 |
| 6978343 | Ichiriu | Dec 2005 | B1 |
| 6980985 | Amer-Yahia et al. | Dec 2005 | B1 |
| 6981205 | Fukushima et al. | Dec 2005 | B2 |
| 6988171 | Beardsley et al. | Jan 2006 | B2 |
| 7020017 | Chen et al. | Mar 2006 | B2 |
| 7028165 | Roth et al. | Apr 2006 | B2 |
| 7032123 | Kane et al. | Apr 2006 | B2 |
| 7043505 | Teague et al. | May 2006 | B1 |
| 7100002 | Shrader | Aug 2006 | B2 |
| 7111293 | Hersh et al. | Sep 2006 | B1 |
| 7162678 | Saliba | Jan 2007 | B2 |
| 7173852 | Gorobets et al. | Feb 2007 | B2 |
| 7184446 | Rashid et al. | Feb 2007 | B2 |
| 7328377 | Lewis et al. | Feb 2008 | B1 |
| 7516292 | Kimura et al. | Apr 2009 | B2 |
| 7523157 | Aguilar, Jr. et al. | Apr 2009 | B2 |
| 7527466 | Simmons | May 2009 | B2 |
| 7529466 | Takahashi | May 2009 | B2 |
| 7571277 | Mizushima | Aug 2009 | B2 |
| 7574554 | Tanaka et al. | Aug 2009 | B2 |
| 7596643 | Merry, Jr. et al. | Sep 2009 | B2 |
| 7681106 | Jarrar et al. | Mar 2010 | B2 |
| 7685494 | Varnica et al. | Mar 2010 | B1 |
| 7707481 | Kirschner et al. | Apr 2010 | B2 |
| 7761655 | Mizushima et al. | Jul 2010 | B2 |
| 7774390 | Shin | Aug 2010 | B2 |
| 7840762 | Oh et al. | Nov 2010 | B2 |
| 7870326 | Shin et al. | Jan 2011 | B2 |
| 7890818 | Kong et al. | Feb 2011 | B2 |
| 7913022 | Baxter | Mar 2011 | B1 |
| 7925960 | Ho et al. | Apr 2011 | B2 |
| 7934052 | Prins et al. | Apr 2011 | B2 |
| 7954041 | Hong et al. | May 2011 | B2 |
| 7971112 | Murata | Jun 2011 | B2 |
| 7974368 | Shieh et al. | Jul 2011 | B2 |
| 7978516 | Olbrich et al. | Jul 2011 | B2 |
| 7996642 | Smith | Aug 2011 | B1 |
| 8006161 | Lestable et al. | Aug 2011 | B2 |
| 8032724 | Smith | Oct 2011 | B1 |
| 8042011 | Nicolaidis et al. | Oct 2011 | B2 |
| 8069390 | Lin | Nov 2011 | B2 |
| 8190967 | Hong et al. | May 2012 | B2 |
| 8254181 | Hwang et al. | Aug 2012 | B2 |
| 8259506 | Sommer et al. | Sep 2012 | B1 |
| 8312349 | Reche et al. | Nov 2012 | B2 |
| 8412985 | Bowers et al. | Apr 2013 | B1 |
| 20020024846 | Kawahara et al. | Feb 2002 | A1 |
| 20020083299 | Van Huben et al. | Jun 2002 | A1 |
| 20020152305 | Jackson et al. | Oct 2002 | A1 |
| 20020162075 | Talagala et al. | Oct 2002 | A1 |
| 20020165896 | Kim | Nov 2002 | A1 |
| 20030041299 | Kanazawa et al. | Feb 2003 | A1 |
| 20030043829 | Rashid et al. | Mar 2003 | A1 |
| 20030088805 | Majni et al. | May 2003 | A1 |
| 20030093628 | Matter et al. | May 2003 | A1 |
| 20030188045 | Jacobson | Oct 2003 | A1 |
| 20030189856 | Cho et al. | Oct 2003 | A1 |
| 20030198100 | Matsushita et al. | Oct 2003 | A1 |
| 20030212719 | Yasuda et al. | Nov 2003 | A1 |
| 20040024957 | Lin et al. | Feb 2004 | A1 |
| 20040024963 | Talagala et al. | Feb 2004 | A1 |
| 20040073829 | Olarig | Apr 2004 | A1 |
| 20040153902 | Machado et al. | Aug 2004 | A1 |
| 20040181734 | Saliba | Sep 2004 | A1 |
| 20040199714 | Estakhri et al. | Oct 2004 | A1 |
| 20040237018 | Riley | Nov 2004 | A1 |
| 20050060456 | Shrader et al. | Mar 2005 | A1 |
| 20050060501 | Shrader | Mar 2005 | A1 |
| 20050114587 | Chou et al. | May 2005 | A1 |
| 20050172065 | Keays | Aug 2005 | A1 |
| 20050172207 | Radke et al. | Aug 2005 | A1 |
| 20050193161 | Lee et al. | Sep 2005 | A1 |
| 20050201148 | Chen et al. | Sep 2005 | A1 |
| 20050231765 | So et al. | Oct 2005 | A1 |
| 20050257120 | Gorobets et al. | Nov 2005 | A1 |
| 20050273560 | Hulbert et al. | Dec 2005 | A1 |
| 20050289314 | Adusumilli et al. | Dec 2005 | A1 |
| 20060039196 | Gorobets et al. | Feb 2006 | A1 |
| 20060039227 | Lai et al. | Feb 2006 | A1 |
| 20060053246 | Lee | Mar 2006 | A1 |
| 20060085671 | Majni et al. | Apr 2006 | A1 |
| 20060087893 | Nishihara et al. | Apr 2006 | A1 |
| 20060136570 | Pandya | Jun 2006 | A1 |
| 20060156177 | Kottapalli et al. | Jul 2006 | A1 |
| 20060195650 | Su et al. | Aug 2006 | A1 |
| 20060259528 | Dussud et al. | Nov 2006 | A1 |
| 20070011413 | Nonaka et al. | Jan 2007 | A1 |
| 20070058446 | Hwang et al. | Mar 2007 | A1 |
| 20070061597 | Holtzman et al. | Mar 2007 | A1 |
| 20070076479 | Kim et al. | Apr 2007 | A1 |
| 20070081408 | Kwon et al. | Apr 2007 | A1 |
| 20070083697 | Birrell et al. | Apr 2007 | A1 |
| 20070091677 | Lasser et al. | Apr 2007 | A1 |
| 20070113019 | Beukema et al. | May 2007 | A1 |
| 20070133312 | Roohparvar | Jun 2007 | A1 |
| 20070147113 | Mokhlesi et al. | Jun 2007 | A1 |
| 20070150790 | Gross et al. | Jun 2007 | A1 |
| 20070157064 | Falik et al. | Jul 2007 | A1 |
| 20070174579 | Shin | Jul 2007 | A1 |
| 20070180188 | Fujibayashi et al. | Aug 2007 | A1 |
| 20070201274 | Yu et al. | Aug 2007 | A1 |
| 20070208901 | Purcell et al. | Sep 2007 | A1 |
| 20070234143 | Kim | Oct 2007 | A1 |
| 20070245061 | Harriman | Oct 2007 | A1 |
| 20070277036 | Chamberlain et al. | Nov 2007 | A1 |
| 20070279988 | Nguyen | Dec 2007 | A1 |
| 20070291556 | Kamei | Dec 2007 | A1 |
| 20070294496 | Goss et al. | Dec 2007 | A1 |
| 20070300130 | Gorobets | Dec 2007 | A1 |
| 20080019182 | Yanagidaira et al. | Jan 2008 | A1 |
| 20080022163 | Tanaka et al. | Jan 2008 | A1 |
| 20080052446 | Lasser et al. | Feb 2008 | A1 |
| 20080056005 | Aritome | Mar 2008 | A1 |
| 20080077841 | Gonzalez et al. | Mar 2008 | A1 |
| 20080077937 | Shin et al. | Mar 2008 | A1 |
| 20080086677 | Yang et al. | Apr 2008 | A1 |
| 20080144371 | Yeh et al. | Jun 2008 | A1 |
| 20080147964 | Chow et al. | Jun 2008 | A1 |
| 20080147998 | Jeong | Jun 2008 | A1 |
| 20080148124 | Zhang et al. | Jun 2008 | A1 |
| 20080163030 | Lee | Jul 2008 | A1 |
| 20080168191 | Biran et al. | Jul 2008 | A1 |
| 20080168319 | Lee et al. | Jul 2008 | A1 |
| 20080170460 | Oh et al. | Jul 2008 | A1 |
| 20080229000 | Kim | Sep 2008 | A1 |
| 20080229003 | Mizushima et al. | Sep 2008 | A1 |
| 20080229176 | Arnez et al. | Sep 2008 | A1 |
| 20080270680 | Chang | Oct 2008 | A1 |
| 20080282128 | Lee et al. | Nov 2008 | A1 |
| 20080285351 | Shlick et al. | Nov 2008 | A1 |
| 20080313132 | Hao et al. | Dec 2008 | A1 |
| 20090003058 | Kang | Jan 2009 | A1 |
| 20090037652 | Yu et al. | Feb 2009 | A1 |
| 20090125671 | Flynn et al. | May 2009 | A1 |
| 20090144598 | Yoon et al. | Jun 2009 | A1 |
| 20090168525 | Olbrich et al. | Jul 2009 | A1 |
| 20090172258 | Olbrich et al. | Jul 2009 | A1 |
| 20090172259 | Prins et al. | Jul 2009 | A1 |
| 20090172260 | Olbrich et al. | Jul 2009 | A1 |
| 20090172261 | Prins et al. | Jul 2009 | A1 |
| 20090172262 | Olbrich et al. | Jul 2009 | A1 |
| 20090172308 | Prins et al. | Jul 2009 | A1 |
| 20090172335 | Kulkarni et al. | Jul 2009 | A1 |
| 20090172499 | Olbrich et al. | Jul 2009 | A1 |
| 20090193058 | Reid | Jul 2009 | A1 |
| 20090207660 | Hwang et al. | Aug 2009 | A1 |
| 20090222708 | Yamaga | Sep 2009 | A1 |
| 20090228761 | Perlmutter et al. | Sep 2009 | A1 |
| 20090292972 | Seol et al. | Nov 2009 | A1 |
| 20090296466 | Kim et al. | Dec 2009 | A1 |
| 20090296486 | Kim et al. | Dec 2009 | A1 |
| 20090319864 | Shrader | Dec 2009 | A1 |
| 20100002506 | Cho et al. | Jan 2010 | A1 |
| 20100037012 | Yano et al. | Feb 2010 | A1 |
| 20100061151 | Miwa et al. | Mar 2010 | A1 |
| 20100091535 | Sommer et al. | Apr 2010 | A1 |
| 20100103737 | Park | Apr 2010 | A1 |
| 20100161936 | Royer et al. | Jun 2010 | A1 |
| 20100199125 | Reche | Aug 2010 | A1 |
| 20100202196 | Lee et al. | Aug 2010 | A1 |
| 20100208521 | Kim et al. | Aug 2010 | A1 |
| 20100262889 | Bains | Oct 2010 | A1 |
| 20100281207 | Miller et al. | Nov 2010 | A1 |
| 20100281342 | Chang et al. | Nov 2010 | A1 |
| 20110051513 | Shen et al. | Mar 2011 | A1 |
| 20110083060 | Sakurada et al. | Apr 2011 | A1 |
| 20110113281 | Zhang et al. | May 2011 | A1 |
| 20110131444 | Buch et al. | Jun 2011 | A1 |
| 20110173378 | Filor et al. | Jul 2011 | A1 |
| 20110199825 | Han et al. | Aug 2011 | A1 |
| 20110205823 | Hemink et al. | Aug 2011 | A1 |
| 20110213920 | Frost et al. | Sep 2011 | A1 |
| 20110228601 | Olbrich et al. | Sep 2011 | A1 |
| 20110231600 | Tanaka et al. | Sep 2011 | A1 |
| 20120096217 | Son et al. | Apr 2012 | A1 |
| 20120110250 | Sabbag et al. | May 2012 | A1 |
| 20120151124 | Baek et al. | Jun 2012 | A1 |
| 20120151253 | Horn | Jun 2012 | A1 |
| 20120151294 | Yoo et al. | Jun 2012 | A1 |
| 20120195126 | Roohparvar | Aug 2012 | A1 |
| 20120239976 | Cometti et al. | Sep 2012 | A1 |
| 20120284587 | Yu et al. | Nov 2012 | A1 |
| 20130036418 | Yadappanavar et al. | Feb 2013 | A1 |
| 20130179646 | Okubo et al. | Jul 2013 | A1 |
| 20130343131 | Wu et al. | Dec 2013 | A1 |
| 20140095775 | Talagala et al. | Apr 2014 | A1 |
| 20140122818 | Hayasaka et al. | May 2014 | A1 |
| 20140143505 | Sim et al. | May 2014 | A1 |
| Number | Date | Country |
|---|---|---|
| 1465203 | Oct 2004 | EP |
| 1 990 921 | Nov 2008 | EP |
| 2002-532806 | Oct 2002 | JP |
| WO 2007036834 | Apr 2007 | WO |
| WO 2007080586 | Jul 2007 | WO |
| WO 2008121553 | Oct 2008 | WO |
| WO 2008121577 | Oct 2008 | WO |
| WO 2009028281 | Mar 2009 | WO |
| WO 2009032945 | Mar 2009 | WO |
| WO 2009058140 | May 2009 | WO |
| WO 2009084724 | Jul 2009 | WO |
| WO 2009134576 | Nov 2009 | WO |
| WO 2011024015 | Mar 2011 | WO |
| Entry |
|---|
| International Search Report and Written Opinion dated Jul. 25, 2014, received in International Patent Application No. PCT/US2014/029453, which corresponds to U.S. Appl. No. 13/963,444, 9 pages (Frayer). |
| International Search Report and Written Opinion dated Mar. 7, 2014, received in International Patent Application No. PCT/US2013/074772, which corresponds to U.S. Appl. No. 13/831,218, 10 pages (George). |
| International Search Report and Written Opinion dated Mar. 24, 2014, received in International Patent Application No. PCT/US2013/074777, which corresponds to U.S. Appl. No. 13/831,308, 10 pages (George). |
| International Search Report and Written Opinion dated Mar. 7, 2014, received in International Patent Application No. PCT/US2013/074779, which corresponds to U.S. Appl. No. 13/831,374, 8 pages (George). |
| Barr, Introduction to Watchdog Timers, Oct. 2001, 3 pgs. |
| Canim, Buffered Bloom ilters on Solid State Storage, ADMS* 10, Singapore, Sep. 13-17, 2010, 8 pgs. |
| Kang, A Multi-Channel Architecture for High-Performance NAND Flash-Based Storage System, J. Syst. Archit., 53, 9, Sep. 2007, 15 pgs. |
| Kim, A Space-Efficient Flash Translation Layer for CompactFlash Systems, May 2002, 10 pgs. |
| Lu, A Forest-structured Bloom Filter with Flash Memory, MSST 2011, Denver, CO, May 23-27, 2011, article, 6 pgs. |
| Lu, A Forest-structured Bloom Filter with Flash Memory, MSST 2011, Denver, CO, May 23-27, 2011, presentation slides, 25 pgs. |
| McLean, Information Technology—AT Attachment with Packet Interface Extension, Aug. 19, 1998, 339 pgs. |
| Park, A High Performance Controller for NAND Flash-Based Solid State Disk (NSSD), Feb. 12 16, 2006, 4 pgs. |
| Pliant Technology, International Search Report / Written Opinion, PCT/US08/88133, Mar. 19, 2009, 7 pgs. |
| Pliant Technology, International Search Report / Written Opinion, PCT/US08/88136, Mar. 19, 2009, 7 pgs. |
| Pliant Technology, International Search Report / Written Opinion, PCT/US08/88146, Feb. 26, 2009, 10 pgs. |
| Pliant Technology, International Search Report / Written Opinion, PCT/US08/88154, Feb. 27, 2009, 8 pgs. |
| Pliant Technology, International Search Report / Written Opinion, PCT/US08/88164, Feb. 13, 2009, 6 pgs. |
| Pliant Technology, International Search Report / Written Opinion, PCT/US08/88206, Feb. 18, 2009, 8 pgs. |
| Pliant Technology, International Search Report / Written Opinion, PCT/US08/88217, Feb. 19, 2009, 7 pgs. |
| Pliant Technology, International Search Report / Written Opinion, PCT/US08/88229, Feb. 13, 2009, 7 pgs. |
| Pliant Technology, International Search Report / Written Opinion, PCT/US08/88232, Feb. 19, 2009, 8 pgs. |
| Pliant Technology, International Search Report / Written Opinion, PCT/US08/88236, Feb. 19, 2009, 7 pgs. |
| Pliant Technology, International Search Report / Written Opinion, PCT/US2011/028637, Oct. 27, 2011, 11 pgs. |
| Pliant Technology, Supplementary ESR, 08866997.3, Feb. 23, 2012, 6 pgs. |
| SanDisk Enterprise IP LLC, International Search Report / Written Opinion, PCT/US2012/042764, Aug. 31, 2012, 12 pgs. |
| SanDisk Enterprise IP LLC, International Search Report / Written Opinion, PCT/US2012/042771, Mar. 4, 2013, 14 pgs. |
| SanDisk Enterprise IP LLC, International Search Report / Written Opinion, PCT/US2012/042775, Sep. 26, 2012, 8 pgs. |
| SanDisk Enterprise IP LLC, International Search Report / Written Opinion, PCT/US2012/059447, Jun. 6, 2013, 12 pgs. |
| SanDisk Enterprise IP LLC, International Search Report / Written Opinion, PCT/US2012/059453, Jun. 6, 2013, 12 pgs. |
| Sandisk Enterprise IP LLC, International Search Report / Written Opinion, PCT/US2012/059459, Feb. 14, 2013, 9 pgs. |
| SanDisk Enterprise IP LLC, International Search Report / Written Opinion, PCT/US2012/065914, May 23, 2013, 7 pgs. |
| SanDisk Enterprise IP LLC, International Search Report / Written Opinion, PCT/US2012/065916, Apr. 5, 2013, 7 pgs. |
| SanDisk Enterprise IP LLC, International Search Report / Written Opinion, PCT/US2012/065919, Jun. 17, 2013, 8 pgs. |
| SanDisk Enterprise IP LLC, Notification of the Decision to Grant a Patent Right for Patent for Invention, CN 200880127623.8, Jul. 4, 2013, 1 pg. |
| SanDisk Enterprise IP LLC, Office Action, CN 200880127623.8, Apr. 18, 2012, 12 pgs. |
| SanDisk Enterprise IP LLC, Office Action, CN 200880127623.8, Dec. 31, 2012, 9 pgs. |
| SanDisk Enterprise IP LLC, Office Action, JP 2010-540863, Jul. 24 2012, 3 pgs. |
| Watchdog Timer and Power Savin Modes, Microchip Technology Inc., 2005, 14 pgs. |
| Zeidman, 1999 Verilog Designer's Library, 9 pgs. |
| Number | Date | Country | |
|---|---|---|---|
| 61858528 | Jul 2013 | US |
